"I don't believe in an America where the separation of church and state are absolute," he told 'This Week' host George Stephanopoulos. "The idea that the church can have no influence or no involvement in the operation of the state is absolutely antithetical to the objectives and vision of our country ... to say that people of faith have no role in the public square? You bet that makes me want to throw up."

However, at a campaign event on the eve of the Michigan primary, the former Pennsylvania senator described his vision for the role of religion in public life.

"I'm for separation of church and state," he said on Monday. "The state has no business telling the church what to do."

During the interview Sunday, Santorum also criticized fellow Catholic John F. Kennedy, who said in a 1960 speech that "I believe in an America where the separation of church and state is absolute."

Santorum said last October that he "almost threw up," when he first read the speech and that Kennedy had thrown "his faith under the bus."